89th American Meteorological Society Annual Meeting

Tuesday, 13 January 2009
Eastern Australian Dust Storm Variability: Result of Multidecadal Pacific Climate System Forcing with Climate Change Implications
Hall 5 (Phoenix Convention Center)
Peter J. Lamb, CIMMS/Univ. of Oklahoma; and L. M. Leslie, R. P. Timmer, and M. S. Speer
Central eastern Australia is a major global source region for atmospheric dust. A striking multidecadal oscillation of dust storm frequency has occurred in this large region since the late-1950s. From 1959-73, there was a pronounced and consistent maximum, after which a sharp 1973-77 decline was followed by a much more dust-free 1977-2006. The dust oscillation was forced locally by strengthening and then weakening of the southerly component of the low level wind over the dust-prone region, which reflected the relative speed of the southerly-southeasterly airflow into southeastern Australia. This multidecadal regional wind oscillation was produced most immediately by latitudinal displacement of the South Pacific Convergence Zone, and also was associated with the more remote sea surface temperature changes of the Pacific Decadal Oscillation (tropical North and extratropical North-Northeast Pacific) and North Pacific Oscillation (central subtropical North Pacific). These Pacific climate system oscillations modulated other key environmental conditions (cloud regime, sunshine duration, rainfall rate) across the Southwest Pacific.

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